Image sensor arrays typically comprise a linear array of photosensors which raster scan an image bearing surface or document and convert the microscopic image areas viewed by each photosensor to image signal charges. High-performance image sensor arrays, e.g., a “full-width array,” include an array of photosensors of a width comparable to the length of a page being scanned, to permit one-to-one imaging generally without the need of reductive optics.
At the time of manufacture, the variation between a plurality of photosensor chips within a given printer/scanner device that make up a linear array or a full-width array (FWA) results in the need for initial calibration of each photosensor chip in the array. Additionally, the variation between each photosensor within a given photo sensor chip may also necessitate an initial calibration. Over time the photosensors and/or photosensor chips in the array may fall out of calibration. This may happen for a number of reasons, i.e., variations in operating temperature, natural degradation of the photosensors over time, and/or natural degradation of the light source over time. Thus, a system and method for calibrating a linear array that can both be utilized during an initial calibration at the time of manufacture, as well as throughout the useful life of the printer/scanner device to account for natural degradation of the photosensors, natural degradation of the light source, and variations in operating temperature would be beneficial. Such a system and method are set forth below.